Presently, communication systems, particularly cellular communication systems, operate on one basic air interface standard. For example there are Analog Mobile Phone Systems (AMPS) whose air interface is described in detail in EIA/TIA (Electronics Industry Association/Telecommunications Industry Association) IS-53 (Interim Standard). Other standards include the presently pending TDMA (Time Division Multiple Access) standard, IS-54, and a CDMA (Code Division Multiple Access) standard, IS-95.
In order to provide compatible systems, subscriber units are being provided which will operate on both, or multiple, systems. These are commonly referred to as dual mode, or multimode, subscriber units. However, in places where newer systems, (TDMA or) CDMA, are available along with an AMPS system, there may be a separate network providing service to the subscriber. In operation, the dual mode subscriber would first attempt to access the CDMA system. Failing this, the dual mode subscriber would attempt to access the AMPS system.
In the future, it is envisioned that the networks will also be dual, or multiple, mode by offering more than one air interface type over which to operate. When this occurs, it will be necessary for the network to determine what type of several air interfaces to which a subscriber, having multiple modes, will be assigned. Therefore, there is a need to provide a method of matching and selecting the appropriate air interface to be used for the communication.